init: flush async file closing

When unpacking the initramfs or when mounting block devices we need to
ensure that any delayed fput() finished to prevent spurious errors.
The init process can be a proper kernel thread or a user mode helper.
In the latter case PF_KTHREAD isn't set. So we need to do both
flush_delayed_work() and task_work_run().

Since we'll port block device opening and closing to regular file open
and closing we need to ensure the same as for the initramfs. So just
make that a little helper.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Link: https://lore.kernel.org/r/CA+G9fYttTwsbFuVq10igbSvP5xC6bf_XijM=mpUqrJV=uvUirQ@mail.gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 279ad28bf4fb148e37cbd9600842a567c813039c..3c5fd993bc7e3e955f322e506bdad8aea8e0edbb 100644 (file)
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -208,6 +208,9 @@ retry:
                                goto out;
                        case -EACCES:
                        case -EINVAL:
+#ifdef CONFIG_BLOCK
+                               init_flush_fput();
+#endif
                                continue;
                }
                /*

diff --git a/init/do_mounts.h b/init/do_mounts.h
index 15e372b00ce704bc1b1e5db6514db3a4dcd654a4..6069ea3eb80d70106d6a8d8b3515d50176353206 100644 (file)
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -9,6 +9,8 @@
 #include <linux/major.h>
 #include <linux/root_dev.h>
 #include <linux/init_syscalls.h>
+#include <linux/task_work.h>
+#include <linux/file.h>
 
 void  mount_root_generic(char *name, char *pretty_name, int flags);
 void  mount_root(char *root_device_name);
@@ -41,3 +43,10 @@ static inline bool initrd_load(char *root_device_name)
        }
 
 #endif
+
+/* Ensure that async file closing finished to prevent spurious errors. */
+static inline void init_flush_fput(void)
+{
+       flush_delayed_fput();
+       task_work_run();
+}

diff --git a/init/initramfs.c b/init/initramfs.c
index 76deb48c38cb16dd779de7ee91b35785b6890579..6554f28fa2dac4c115d67f104b65e7d3fc060086 100644 (file)
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -16,9 +16,10 @@
 #include <linux/mm.h>
 #include <linux/namei.h>
 #include <linux/init_syscalls.h>
-#include <linux/task_work.h>
 #include <linux/umh.h>
 
+#include "do_mounts.h"
+
 static __initdata bool csum_present;
 static __initdata u32 io_csum;
 
@@ -736,8 +737,7 @@ done:
        initrd_start = 0;
        initrd_end = 0;
 
-       flush_delayed_fput();
-       task_work_run();
+       init_flush_fput();
 }
 
 static ASYNC_DOMAIN_EXCLUSIVE(initramfs_domain);